Many types of electrochemical cells utilize a liquid electrolyte to support electrochemical reactions within the cell. For example, a metal-air electrochemical cell system may comprise a plurality of cells, each having a fuel electrode serving as an anode at which metal fuel is oxidized, and an air breathing cathode at which gaseous oxygen from ambient air is reduced. Such a cell may also comprise an electrolyte to communicate the oxidized/reduced ions between the electrodes. For example, see U.S. Patent Publication No. 2009/0284229, incorporated in its entirety herein by reference. In some electrochemical cell systems comprising a plurality of electrochemical cells, the electrolyte may be shared by multiple cells. For example, the electrolyte may flow in series from one cell to another, such as is described in U.S. patent application Ser. No. 12/631,484, incorporated herein in its entirety by reference. In other electrochemical cell systems, the electrolyte may be shared by multiple cells, but may flow partially in parallel.
In some electrochemical cell systems, various gasses may evolve during the charging and/or discharging of the cell. Such gasses may be harmful to the cell, and may damage or impede performance of the cell. For example, in some cases the cell may be harmed due to the evolved gasses increasing pressure within a confined area in the cell. In some cases, the cell (and potentially its surroundings) may be harmed due to the evolution of a potentially volatile gas or combination of gasses. Some electrochemical cells are configured to disperse such gasses by including vents therein, so that gasses may escape into the ambient environment. Other electrochemical cells may be configured with pressure relief valves, which are typically closed, however open when the pressure within the cell exceeds a threshold amount.
Among other improvements, the present application also endeavors to provide an effective and improved way of controlling the discharge of gasses within the cell, without adversely affecting the flow of liquid electrolytes within the cell and/or the performance of the cell during operation.